Left limit of break 1 from non-inclusion of Pfk (FBrf0098753) Right limit of break 1 from inclusion of Hr46 (FBrf0093560) Left limit of break 2 from inclusion of psq (FBrf0086124) Right limit of break 2 from non-inclusion of psq (FBrf0086124)

The Df(2R)12 chromosome acts as a dominant weak suppressor of telomeric silencing (assayed using the effect of the chromosome on the eye colour phenotype of flies carrying "P{wvar}KR3-2", a stable "brown-red" variant of the P{3'WP-2,wvar}2Lt insertion), but this is a false positive result (the suppressor is not within the bounds of the deficient region) because the suppressor maps to the tip of 2L rather than to the site of the deficiency.